1. Field of the Invention
The present invention relates to vehicle wheels and more particularly to lightweight automotive wheels made of aluminum. Still more particularly, the present invention relates to modular, high performance automotive wheels.
2. Description of the Prior Art
Many prior art high performance wheels are three-piece types in which a pair of rim sections are secured by means of rivets or otherwise to a center section. Generally, all three pieces of the wheel are formed of aluminum. In order to provide sufficient strength yet minimize the weight of the wheel, the center section has a relatively thick cross section, whereas the rim portions have a thinner cross section. One difficulty encountered in the manufacture of such wheels is that of achieving proper registration of the parts to ensure that they are all coaxial. In addition, the three-piece construction is more complicated, and therefore more expensive, than a typical two-piece wheel.
U.S. Pat. No. 3,826,538, issued to Ray W. Lipper and assigned to Center Line Tool Co., Inc., the same assignee as the present application, discloses a two-piece wheel construction in which two wheel halves are provided and are aligned by means of a centering element including a disk-shaped portion having a central opening and an integral cylindrical collar along the inner circumference thereof. Although the structure provides substantial improvements over prior art wheels, it has the disadvantage of requiring a centering element in addition to the wheel halves. Furthermore, the center section of the resulting wheel is a laminated structure which has a material thickness which is twice that of the rim portions. This structure therefore does not enable the relative thickness of the different portions of the wheel to be optimized.
In order to securely clamp the bead of a tire with respect to the wheel, locking rings which attach to the wheel rim have been developed. Recent locking rings are comprised of one-piece forged aluminum rings which are secured to the wheel rim by means of bolts or the like. Although such locking rings provide the advantage of securely holding a tire, they have the disadvantage of increasing the weight of the wheel.